The objective of this research is to study the biochemical controls involved in the development and function of lung tissue. Both hormonal and genetic factors are analyzed using isotopic and immunochemical techniques. Corticoids are apparently involved in maturation of the lung's ability to produce surfactant material. A specific binding protein "receptor" in the soluble part of the lung tissue of different species has been identified and characterized in this and other laboratories in the past year. The properties of this receptor are examined during perinatal development of the lungs in rats and sheep. This binding receptor will also be elucidated in human autopsies to assess the fate of the receptor in lungs of children suffering from hyaline membrane disease. The properties of lung chromatin and its components (nonhistone proteins) during ontogeny will be studied, utilizing a novel immunochemical method developed in this laboratory. This method can measure possible changes in the structure and function of chromatin, and will also be used to assess chromatin during lung deficiency as hyaline membrane disease.